Aeroplane



J; FOLINO A ril 26, 199.2.

AEROPLANE Filed March 13, 1951 s Sheets- Sheet 2 IN V EN TOR.

y 7024;, BY i A TTORNEYS.

April 26, 1932. J FQLINQ 1,855,911

AEIROPLANE Filed March 15, 1951 a Sheets-Sheet 3 INVEN TOR.

'4 ?-&; 0

ATTORNEYS.

Patented Apr. 26, 1932 uNrrso STATES PATENT orrrcis JOHN FOLINO, 0F WILKINSBURG,PENNSYLVANIA, JASSIGNOR' OF onn roun'rnao WILLIAM B. JASPER/1', OF MOUNT LEBANON, PENNSYLVANIA AERorLAnE Application filed; March 13, 1931. Serial 110,522,330.

This invention relates to a mechanical pilot for automatically controlling aeroplanes in their flight, and it is among the objects thereof to provide apparatuswhich shall be adapted to automatically maintain an aeroplane in a predetermined course of straightfliglit, which shall be adapted to automatically correct any change or variation affecting the horizontal stability and equilibrium of the plane and which shall be adapted to act to maintain the plane substantially at uniform height above sea level.

A further object of the invention is the N provision of simple and durable mechanical means, electricallyoperated, to control the rudder, elevator and ailerons of an aeroplane in response to automatic control switches and other control devices which, although inn stantly responsive to variations or deviations from the course of flight, shall not be so sensitive as to render the control operative;

when the plane is subjected to undue vibration or air bumps.

lit is a primary object 01 the invention to provide. a novel form of tilting switch which is especially designed to control the elevator an d aileron operating mechanism.

A further object 01 the invention is to provide means for rendering the automatic elevator control means inoperative when the aeroplane is under control of the automatic altitude regulating means.

It is a still further object of the invention 5 character which shall be of simple and durable mechanical construction, whichshall be reliable and dependable for use for which it c1011 of a mechanical control mechanism aeroplanes embodying theprmmplesof 11s invention to provide a naratus of the above desi 'nated ure 1. is a top plan view partially in I Figures Qand 3 are end and sideelevational views, respectively, of thedeviceshownin Figure 1:

Figure l a longitudinal cross-sectional view of a special type of control switch:

Figure 5. a cross sectional view' of the switch taken along the lines VV., Figure 4:

Figure 6 a cross sectional viewof a plunger employed inthe mechanism of; Figure 7, illustratingthe cable connection therewith:

Figure 7 a wiring diagram of the. electrical connections. of the various. control ,elements "and Figure 8 a view in-perspective of analtitude rectifier which is employed in a manner to be herein setforth.

Before describing the invention .in detail, it is well to consider thecharacteristicsof the modern aeroplane and the means commonly employed for controlling-it in flight The 79 plane is supportedinflight bythe air. pressure produced under the wings ofthetplane,

. and. even with the highldegree of stability claimed by plane designers, itiswell known that a plane in flight is subjected more orless to inclinations and deviationswhich: must be promptly corrected tomaintain equilibrium,.stability and direction of flight.

As. now generally practiced, such. inclinae tions. and deviations. are corrected by the pilot by manually operablemeans, namely, the joy stick and pedals, and there aresix correcting actions required to maintain stability and direction; two controlling the ailerons or the rolling axis of the plane; two135 controlling the elevational or pitch axis and two controlling the rndderfor direction; and by properly manipulatingthe joy stick and pedals, the control elements are. moved. exactly as required. The corresponding actions to are eifected through mechanical linkage or gearing having cable connections withthe operating shaftsof the joy stick and pedals, all of which being essentially in tension when acting. upon the respective devices, whereby two cables are required to operate each control. for the exertion of opposed controlling forces.

In accordanceiwith the present. invention, the control is automatically 'efiected through 100 mechanism, the character of which will become apparent from a detailed description of the structure disclosed in the accompanying drawings.

lVith reference to Figures 1 to 5 inclusive of the drawings, the numerals 1-1, 22, 3 3, designate groups of magnetic coils or solenoids which are secured to an iron frame 4 which constitutes a common magnetic iron core for all of the solenoid windings. The solenoids are maintained in proper alinement by tubes 6 preferably constructed of aluminum. to minimize their weight and which are secured to the frame 4 by'screws 5. Two solenoids constituting a group, are arranged in coaxial alinement' and are adapted to act upon movable plungers 7' disposed for axial movement in tubes 6 in which they are normally biased in the direction of the solenoids by coil springs 8. Springs 8 are adapted to abut against end rings 9 secured in the ends of the aluminum tubes 6, as shown in cross section in Figure 1.

Each solenoid acts upon its own individual plunger and each pair of plungers are oined by a cable 10 in the form of a loop which is disposed around sheave wheels 11 and fastened at its loose ends to the plungers i in the manner shown in Figure 6 of the drawings.

The ends of the cable loop are secured by clamping jaws 12 which 't into a hollow screw plug 13 having an external thread 14 which interacts with the thread 15 provided centrally in the plunger 7. A hollow screw 16 and a cap screw 17' secure the clamping members 12 in the plug 13 so that when the ends of the cable 10 are thus secured they cannot be pulled out of their connections with the plungers 7.

Referring to Figures 2 and 3 of the drawings, the looped cable 10 passing over the sheave wheels 11 are connected to a control cablev 18 by meansof clamps 19, the control cable 18 being movable with the cable loops 10 in response to varying actions of the magnetically actuated plungers 7. The control cable 18 has its free ends 20 and 21 connected to the control surfaces of the aeroplane, such as the rudder, elevator, or ailerons and the degree of movement of the control cable is dependent upon the length of stroke or the movement of the plungers 7.

As shown in Figures 1 and 2, there are three groups of solenoid actuated plungers each of which constitutes a control in two directions for the cables, thus thegroups operated by solenoids 1-1, may be connected by the control cable ends 2021 to the rudder, the groups 22' by their connection to control cable ends 2223 to the elevator; the group 33 by their control cable ends 24-25 to the ailerons. The frame 4 of the device may be mounted onuprights26 of the pilots chair by means of cross bars 4 which are clamped thereto by screws 27.

To provide for suitable adjustment of the stroke of the plungers 7 the sheave wheel spindles 28 and 29 on which Wheels 11 are mounted, are secured at their ends in brackets 30 having elongated slots 31, Figure 3, in which they are freely movable in a horizontal direction.- The spindles 28 and 29 are provided with end collars 32 to hold them in frame 4 and spacing collars 34 are provided for axially spacing the sheave wheels or cable pulleys 11 which are free to rotate independently of the rotary movement of the spindles.

Spindles 28 and 29 are normally biased towards. each other by the coil springs 8 within the tubes 6 and adjustable abutments are provided against which the shafts are held by the springs. The abutments consist of slotted sleeves 36 having screw threaded ends 37 disposed in threads of the slots 31 of brackets 30. The adjustable sccw 37 varies the spacing of the abutments to vary the center distance of the spindles 28 and 29 and the screw mechanism in turn is operated through a crank 38 which is connected through a worm gear and worm screw 39 and 40, respectively, with the adjusting screws, the being all rendered adjustable simultaneous ly by operation of the hand crank 38.

By turning the hand crank 38, the spindles 28 and 29 may be contracted or expanded with respect to the solenoids, thereby moving the pulleys towards or away from the coils; the springs 8 act upon plungers 7 to at all times hold the sheave wheel spindles against the movable abutments 36 of the adjusting screw mechanism. By means of this adjustment, provision may be made to adapt the mechanism to different sized planes and to vary the stroke of the plunger-s as cesired.

In Figure 1, a plurality of mercury switches 41 and 42 are shown with their longitudinal axes disposed at right angles each other and coincident with the longitndinal and transverse axes of the aeroplane in which they are mounted. Although the switches are shown in Figure 1 as mounted adjacent the control mechanism, they may be mounted in any suitable portion of the fuselage or wing structure such as the dashboard, for example. The switches are of the type illustrated in Figures 4 and 5 of drawings and consist of a housing 43 of any suitable insulating material such as glass having its ends diverging at one side of its long tudinal center line, the center of the housing being mounted with the apex 44 extending upwardly in the manner shown in Figure 4, this being the normal and operating position of the switch. The switch housing 1:; filled with mercury 45 to the extent that a bubble 46 is produced which normally rests in the apex of the housing as shown. The housing or switch chamber is preferably es;- hausted and the chamber filled with an in sulating inert non oxidizing gas or liquid to prevent .QXldlZfitliOIlTOf thevmercury. Terminals 47 and .48vare provided in the ends of the switch, the .terminaluends.projecting into the mercury as shown: and a terminalirl) is provided in one end of the switch with its end projecting into the mercury a substantial distance to assure anetficient' electric connection with the mercury at all times. 'Ter-- minals 47, 18 and 49 are suitably embedded and sealed in the ends of the switch to prevent the escape of the-mercury, and are connected to electrical conductors in a power circuit ina manner to be hereinafter described in connection with Figure 7 of the drawings. a

The switches are designedto operatein conjunction with aseries of relays which are of the normally closed type so that when the bubble 4670f the switch opens the electrical circuit'of either of the terminals 47 or as, the corresponding relay=will be open circuited to release its armature which is a movable switch arm designed to close an electric circuit toproduce energization of one of the solenoids shown in Figure 1 ofthe. drawings. The switch may be of any suitable cross sectional area, as for example the cylindrical cross section shown inFigui-e of the drawings, and by means of its angular housing construction, the bubble 46 is supported by the head pressure of the mercury which is equal to the volume of displacement from the apex of the housing to the upper terminals 47 and 48, and it is so constructed to prevent the bubble 46 from responding to vibrations, air-bumps, or slight variations of the plane.

\Vith reference to Figure 7 of the drawings, the solenoids and switches are shown connected in an electrical circuit energized by a generator 50 and these elements are further illustrated as associated with other control mechanism as follows: Solenoids 1-1 are connected by their terminals 51 and 52 to a power line 53 leading to thegenerator and at their terminals 54c and 56 to normally open contacts 56 and 57 of relays 58 and 59, re spectively, which when de-energized, actuate movable armatures 60 and 61 which are biased by springs 62 to make contact with the terminals 56 and 57 to energizethe solenoids 1 and 1'.

Solenoids 22 are connected at one side by a conductor 68 to the power line. 58 and through their other terminals 6 l65 to'relays 66 and 67 respectively. Similarly solenoids 3 and 8 are connected through conductor 68 to the power line and by their terminal connections 69 and 70 to relays 71 and 7 2,.respectively. Relays 67 and 66 and 71 and 7 2 are connected tothe mercury switches 41 and 4-2 to be responsive .totheir. tiltingv action as ex- .plained in connection with Figure. 1 of the drawings. V

An earth inductonf? i is- (IOIIIIBQtGQttOiiZllG grid element 75 ofa pair of electron tube generators 75a and 75?), the plates 76 of which are connected to the relays 58 and 59. The filaments 77 are connected through a conductor '78 to a segment 90 of a control switch. The elevator controlling solenoids 22 are further controlled by relays 80 and 81 in response to an altitude rectifier generally designated at 82, Figure 8, of which the arm 83 constitutes the movable arm 83 of the wiring diagram which is adapted to contact terminals 84 and 85 of the relays 80 and 81, re spectively. The -movable arm 83 is at all times electrically connected with a solenoid 86 which when energized breaks the circuit of the conductor 87 bymoving its armature 88 out of contact therewith.

The electrical connection to the positive terminal of the'generator 50 is effected through the segment switch by means-of a movable arm 89 and contact segments 90, 91 and 92, which segments are of difierent lengths to permit energizing some of the circuits preliminary to establishing electrical contact with all three control segments.

The operation of the device is briefly as follows: When the plane has taken oii and reaches the desired altitude, the arm 89 is moved to contact with the segment 90, thereby energizing filaments 77 of the electron tube generator to preheat them before making contact with segment 91 and through segment 91 the normally closed relays 5859, 6667, and 71-72 are energized before the normally open relays 80 and 81 which latter are energized when the arm 89 passes to the short segment 92.

Once the automatic control mechanismis placed in operation, any deviation of the plane or any unstabilizing effects are rere sponded to and corrected as follows: If the nose of the plane suddenly drops, the bubble as of the switch a1 will open circuit the terminals 47, thus breaking the circuit of relay 67 whichreleases its armature and establishes the electrical circuit of solenoid 2 which as previously explained controls the elevators through its plungerby causing movement of the end 28 of the control cable and-when the nose of the plane has been i righted, the bubble 46 will return to its cent-er position, thus reestablishing the circuit to energize relay 67 and withdraw the armature .to open circuit and deenorgize solenoid 2'.

ailerons which immediately stabilize the lane.

The altitude of the plane is maintained in response to the altitude rectifier 82 which controls the elevator operating solenoids 22 through relays 80 and 81, the relay 86 functioning to prevent the simultaneous oppositional functioning of the )electrical control switch 41.

The altitude rectifier 82 operates as follows. lVhen the plane has reached the altitude desired for the course of flight, its valve is opened to equalize the air pressure inside and outside of the expansion box 82' and while the air pressure is thus equalized, the indicator arm 83 will be in neutral position in which position it is inoperatively disposed out of contact with members 84 and 85. It a previous nose dive corrected through the electric switch 41 has resulted in the loss of some altitude, the effect of the loss in altitude will increase the outside air pressure causing contraction of the expansion box 82 and such contraction will operate lever 83 to engage contact 84: which in turn causes relay 80 to be energized to close the power circuit leading to solenoid 2 and to thereby operate the elevator. Simultaneously, with the closing of the contact 84-, solenoid 86 is energized to open the circuit 87 of the relays controlled by the electric switch il so as to prevent any counter action or interference of the switch 41 with the altitude rectifier. In a similar manner, if the aeroplane has reached a higher altitude, the expansion box 82 will expand due to the difference in the internal and external air pressure and arm 83 will move into contact with the terminal 85, thus energizing the solenoid 81 and establishing the circuit with solenoid 2 to operat the elevator, resulting in the plane gliding to a lower altitude, and simultaneously the relay 86 is energized to prevent interference by the electric switch 41.

The automatic steering of the plane is effected through the earth inductor 74 as fol lows: The relays 58 and 59 are energized by the electrical energy of the electron tubes and hold their respective armatures 60 and 61 in normally closed position in which position the rudder solenoids 11 are deenergized. The rudder maintains its position regardless of how the stability of the plane may be affected, and the earth inductor is also maintained neutral by its internal electro-motive forces which are completely balanced and no current flows in its external circuit which is the grid circuit 75 of the electrode tubes 7 5a and 75b. l/Vhen the plane deviates from a straight course, the change in direction will result in a change of the relative position of the brushes of the earth inductor with the earth magnetic field, thereby setting up current in its external circuit. This current will be negative at one of its terminals and positive at the other, depending upon which direction the plane has deviated from the straight course. When a negative charge is imparted to the grid of the electron tubes,v a substantial decrease of the internal electronic flow will take place between the filament and plate, thus. deenergizing the relays 58 and 59 as the case may be, to such extent that it releases its armature to temporarily energize the rudder control solenoids 1 or 1 thereby instantly exerting a pull on the rudder to restore the plane to its former direction. When this is accomplished, the normal flow in the electron tube and associated relay will be re-activated by the earth inductor, returned to its former neutral posi tion with resultant deenergizing of the rudder controlling solenoid.

It is evident from the foregoing description of this invention that the electric control system for mechanically and automatically piloting a plane provides for the correction of all deviations from the straight course and provides for stabilizing the plane in response to any deviations, except vibrations or other minor operating characteristics of the plane which would render the apparatus useless.

It is apparent that the automatic pilot mechanism may be employed in conjunction with the standard form of control by connecting the control cable to the operating shafts of the joy stick and foot pedals without in any manner interfering with standard control equipment and without making any provisions for such joint control in the design or construction of the aeroplane.

Although the invention has been illustrated as embodied in a particular form of structure and arrangement of parts, it will be obvious to those skilled in the art that various modifications may be made without departing from the principles herein set forth.

I claim:

1. In an aeroplane, the combination with controls for stabilizing its pitching axis, of electromagnets for actuating said controls, means separate from said stabilizing means for controlling the altitude of the aeroplane, an electrical circuit for said stabilizing and altitude control means, and means for rendering said stabilizing means inoperative when said altitude control means is op erating.

2. In an aeroplane, the combination with controls for stabilizing its pitching axis, of electromagnets for actuating said controls, means separate from said stabilizing means for controlling the altitude of the aeroplane, an electrical circuit for said stabilizing and altitude control means, means in said circuit responsive to the pitching of the plane for energizing said electromagnets, means in said circuit for energizing said altitude controlling means, and means for rendering said stabilizing means inoperative when said altitude control means is operating.

3. In an aeroplane, automatic control mechanism comprising an iron frame, a plurality of electromagnets mounted on said frame, a plurality of movable armatures adapted to be actuated by said electromagnets, a pair of shafts in spaced relation with said frame, sheave wheels mounted on said shafts, con trol cables passing around said wheels and secured to said armatures, and means for adjusting the spacing of said shafts with said magnets to vary the distance of movement of said armatures.

4, In an aeroplane, automatic control mechanism comprising an iron frame, a plurality of hollow electromagnet coils mounted in pairs on said frame, each pair being in coaxial alinement, plungers movable in said coils, the plungers of each pair of coils being joined by a cable looped around a pair of pulleys and control cables fastened to said plunger connecting loops.

5. In an aeroplane, automatic control 1nechanism comprising an iron frame, a plurality of hollow electromagnet coils mounted in pairs on said frame, each pair being in coaxial alinement, plungers movable in said coils, the plungers of each pair of coils be ing joined by cable looped around a pair of pulleys, control cables fastened to said plunger connecting loops, and means for simultaneously separating or contracting said pulleys to vary the stroke of said plungers.

6. In an aeroplane, automatic control mechanism comprising a frame constituting an iron core for a plurality of electromag net coils, a plurality of hollow coils mounted in pairs in coaxial alinement on said frame, a movable plunger disposed in each of said coils, a pair of shafts having their axes disposed transversely to the axes of said plungers, sheave wheels mounted on said shafts, cable loops connecting each pair of cooperating plungers and passing around said sheave wheels, means for simultaneously adj usting both of said shafts to vary the length of the cable loops and the stroke of said plungers, and control cables connected to said loops.

7 In an aeroplane, the combination with elevator controls and aileron controls of automatic means for actuating said controls to stabliize the plane about its pitching and rolling axis, said means comprising electromagnets designed to exert a positive force for either direction of operation of said con trols, an electrical circuit connecting said electromagnets to a source of electrical energy, and switches for automatically controlling said circuit to energize said electromagnets in response to pitching and rolling of said aeroplane, said switches comprising a column of mercury of inverted V-shape having the mercury electrically connected in said circuit and being adapted to open said circuit in the manner specified.

8. In an aeroplane, automatic steering control comprising, a pair of electromagnets for actuating the rudder, an earth-inductoncompass-armature having a pair of brushes connected to power amplifiers, a pair of relays controlling the flow of current to said electro-magnets and connected to be energized by said power amplifiers, said earth-inductorcompass-armature being responsive to deviations from a set course to energize said magnets and actuate the rudder controls.

9. In an aeroplane, the combination with elevator controls and aileron controls of antomatic means for actuating said controls to stabilize the plane about its pitching and rolling axes, said means comprising electrical operating means adapted for exerting positive force for either direction of operation of said controls, an electrical circuit coniecting said operating means to a source of electrical energy, and switches for automatically controlling said circuits to energize said operating means in response to pitching and rolling of said aeroplane, said switches comprising a column of mercury of inverted V- shape having the mercury electrically con nected in said circuits, and being adapted to open said circuits in the manner specified.

In testimony whereof I have hereunto set my hand.

JOHN FOLINO.

Lil 

